CHARLESTON, S.C. 
Jon Huntsman staked his entire presidential campaign on New Hampshire in the hopes he could emerge from the shadow of fellow Mormon Mitt Romney to become a legitimate competitor.

But less than a week after a disappointing third-place finish in the Granite State's primary, Huntsman decided to withdraw and back Romney.

Campaign officials say Huntsman will endorse Romney because he believes Romney is the best candidate to beat President Barack Obama in November. Campaign manager Matt David said Sunday that Huntsman will announce his withdrawal at an event in Myrtle Beach, S.C.

Huntsman was almost invisible in a race often dominated by Romney. While other candidates were starting to campaign, Huntsman was half a world away, serving as Obama's ambassador to China until he resigned in late April.